In CAD applications, it is important to be able to transform two-dimensional representations of objects into solid representations. The automobile and aircraft industries were two of the first to exploit this function for mechanical assemblies. Examples of general CAD systems are disclosed in U.S. Pat. Nos. 4,962,472; 4,849,913; and 4,912,664.
U.S. Pat. No. 4,849,913 discloses a method for the design and construction of composite parts by logically determining the geometric definitions for each ply contained in the composite part. This information can be used by subsequent analysis routines to determine the optimal method for manufacturing the part. Thus, the physical relationship of each of the parts and their correlating features are available for use by the system. However, the CAD system does not have any ability to dynamically alter the dimensions of a solid based on a change in distance between a plurality of faces.
A face is used to refer to an unbounded plane. Unbounded refers to the fact that no limits are placed on the plane dimensions. A loop is a bounded area of a face. Boundary elements comprise the loop. For example, the four lines forming the edge of the plane are boundary elements. A Vertex is an endpoint of an edge. Vertices are calculated by finding the intersection of three (3) intersecting plane equations. A loop table contains information defining all the loops contained in the solid object.
The subject invention overcomes the need to pre-program relationships between CAD geometries and allows a user to dynamically alter a solid geometry on the basis of changes made in a face.